Global is providing diving services to assist with the demolition and removal of an abandoned offshore marine terminal. Existing structure is supported on concrete piling,scope of work involves the removal of an abandoned pipeline as well as assistance with cutting of concrete piling below mud line.
Project Tag: Dive Support Vessel (DSV)
Global Diving & Salvage is providing a dive platform and crew to perform a survey along the alignment on a high pressure natural gas pipeline that crosses the Sacramento River. This survey is being done in preparation of an upcoming river deepening project,from Sacramento to the San Francisco Bay. Divers are using probes to penetrate the river bottom to determine the amount of cover over the pipeline.
Diver performs underwater inspection of the University of WA research vessel the Tommy Thompson.
A live-aboard vessel sank at it moorage on the Duwamish River. Global Diving was contracted by Department of Ecology to mitigate any potential fuel release as well as raise the vessel and remove it from the water. Containment boom was deployed around the vessel as well as various locations around marina to mitigate the spread of fuel in the river current. The fuel vents and caps were sealed. Lifting straps were run under the vessel. A derrick was brought to the site to lift the vessel off bottom. Once on the surface,water was pumped from the hull.
Cheesman Dam,located at 6,842 feet of elevation,is a primary reservoir for Denver Water who provides the potable water to Denver,CO and surrounding areas. Completed in 1905,it was built by Italian Master Masons using finely set and mortared granite blocks. Cheesman was a technological masterpiece and landmark of civil engineering for decades to come.
The Upstream Control Project,Phase 1,encompassed the replacement of three internal gate valves with new hydraulic slide gates located on the upstream face of the dam. The first step was to upgrade the existing Auxiliary,Mid and Low Level outlets,located at 60′,150′,and 200′ deep respectively.
Diver’s worked off of 80-foot by 80-foot sectional barge platform on the reservoir. Due to the depth and the amount of work required a combination of surface and saturation diving was utilized. The Auxiliary level work was done using surface supplied air while the mid and low level outlet work was done using saturation diving.
The original bypass outlets,tunneled through the canyon wall,were enlarged to accept new stainless steel spool pieces,one weighing 29,000 pounds and other two weighing 14,000 pounds each. Divers drilled holes at predetermined location and used underwater explosives to enlarge the openings to accept the new spool pieces. The spools were installed just inside the canyon wall,secured in place with epoxy anchors drilled into the native material,and securely grouted to provide a leak free seal. The new stainless steel slide gates were then mounted to the face of the spool pieces and protected by trash racks to prevent rubble from entering the intake system.
The new valves are operated from a new control structure built on the crest of the dam. This structure houses the hydraulic pump unit and controls which operate the valves. To connect the hydraulic tubing to the valves,holes were drilled from the crest of the dam,exiting into the reservoir next to the gate locations. Hydraulic tubing was installed into the holes and secured in place with grout,connecting the controls on the surface to the individual valves.